Medication reservoir

ABSTRACT

A method and apparatus for a connection interface between a reservoir or syringe, infusion set tubing, and an infusion pump is provided. A base is provided which is adapted to receive a reservoir. The base has a base engagement member, such as a detent, projecting therefrom. A cap is provided which is adapted to receive the base. The cap includes a first cap engagement member, such as a detent opening, which is adapted to removably engage the base detent. The cap further includes a second cap detent opening which is adapted to removably engage the base detent. A piercing member, such as a needle, is disposed in the interior of the cap in such a manner that the needle is separated from the reservoir septum when the base detent is in the first cap detent opening, and the needle pierces the reservoir septum when the base detent is in the second cap detent opening. When the reservoir, the base and the cap are connected to form an integrated unit, this unit is then capable of being inserted and secured in the infusion pump housing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from U.S. patent application Ser. No.12/361,203, filed Jan. 28, 2009, which claims priority from U.S. patentapplication Ser. No. 10/923,133, filed Aug. 20, 2004, now U.S. Pat. No.7,628,782, which claims priority from U.S. patent application Ser. No.10/328,393, filed Dec. 23, 2002, now U.S. Pat. No. 7,658,734, whichclaims priority from U.S. patent application Ser. No. 09/428,818, filedOct. 28, 1999, now U.S. Pat. No. 6,585,695, which claims priority fromprovisional patent application No. 60/106,237 which was filed on Oct.29, 1998 and which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to improvements in syringe andreservoir interfaces for use in infusion pumps such as those used forcontrolled delivery of medication to a patient. More specifically, thisinvention relates to an improved connection interface between areservoir or syringe, infusion set tubing, and an infusion pump.

2. Description of the Related Art

Infusion pump devices and systems are relatively well-known in themedical arts, for use in delivering or dispensing a prescribedmedication such as insulin to a patient. In one form, such devicescomprise a relatively compact pump housing adapted to receive a syringeor reservoir carrying a prescribed medication for administration to thepatient through infusion tubing and an associated catheter.

The infusion pump includes a small drive motor connected via a leadscrew assembly for motor-driven advancement of a reservoir piston toadminister the medication to the user. Programmable controls arenormally provided for operating the drive motor continuously or atperiodic intervals to obtain a closely controlled and accurate deliveryof the medication over an extended period of time. Such infusion pumpsare utilized to administer insulin and other medications, with exemplarypump constructions being shown and described in U.S. Pat. Nos.4,562,751; 4,678,408; 4,685,903; 5,080,653 and 5,097,122, which areincorporated by reference herein.

Infusion pumps of the general type described above have providedsignificant advantages and benefits with respect to accurate delivery ofmedication or other fluids over an extended period of time. The infusionpump can be designed to be relatively compact as well as waterresistant, and may thus be adapted to be carried by the user, forexample, by means of a belt clip. As a result, important medication canbe delivered to the user with precision and in an automated manner,without significant restriction on the user's mobility or life-style,including the ability to participate in water sports.

Infusion sets refer to the tubing and connection apparatus which providea path for the medication to flow from the reservoir or syringe locatedin the pump to the user. The connectors for attaching the infusion settubing to the reservoirs can take various forms. A luer connection is acommonly used connection method. Nevertheless, it remains desirable todevelop improved designs of connection methods to facilitate infusionprocedures and to provide suitable interface connections which are waterresistant so as to permit a user to participate in water sports.

SUMMARY OF THE PREFERRED EMBODIMENTS

An apparatus for connecting a reservoir having a septum and a base to aconduit, such as infusion set tubing, is provided. In certain aspects ofthe present invention, the apparatus comprises a cap and a releasablecoupler which is adapted to releasably couple the base to the cap in oneof two positions. A piercing member, such as a needle, is coupled to theconduit. The needle is disposed in the cap in a position other than theinterior of the reservoir when the base is in the first position. Theneedle is further disposed to pierce the reservoir septum when the baseis in the second position.

In another embodiment, the apparatus is used for connecting a reservoirhaving a septum and a base to a housing as well as to a conduit. Thehousing has a housing engagement member, such as a thread. The apparatuscomprises a cap and a releasable coupler which is adapted to releasablycouple the base to the cap in one of two positions. A piercing member,such as a needle, is releasably coupled to the conduit. The needle isdisposed in the cap in a position other than the interior of thereservoir when the base is in the first position. The needle is furtherdisposed to pierce the reservoir septum when the base is in the secondposition. The cap further includes an engagement member, such as athread, which is adapted to engage with the housing engagement member.

In another embodiment, the cap further includes a vent port which iscovered with hydrophobic material. This permits air to pass through thecap while preventing water from doing so.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded, perspective view of a medication reservoirconnection interface apparatus.

FIG. 2 is a perspective view of a cap used as a medication reservoirconnection interface apparatus.

FIG. 3 is an exploded, perspective view of an alternative embodiment ofa medication reservoir connection interface apparatus.

FIG. 4 is a side, cut-away view of a cap used as a medication reservoirconnection interface apparatus.

FIG. 5 is a side, plan cut-away view of a medication reservoirconnection interface apparatus with a needle inserted into a reservoir.

FIG. 6 is a side, plan cut-away view of a medication reservoirconnection interface apparatus which is inserted into a pump housing.

FIG. 7 is a perspective view of an alternative embodiment of amedication reservoir connection interface apparatus.

FIG. 8 is a perspective top view of an alternative embodiment of amedication reservoir connection interface apparatus which is securedinto a pump housing.

FIG. 9 is a perspective view of an alternative embodiment of amedication reservoir connection interface apparatus.

FIG. 10 is an exploded, perspective view of a cap used as a medicationreservoir connection interface apparatus.

FIG. 11 is a perspective view of a medication reservoir connectioninterface adapter.

FIG. 12 is a cross-sectional view of a medication reservoir connectioninterface adapter.

FIG. 13 is a perspective view of an alternative embodiment of a cap usedas a medication reservoir connection interface apparatus.

FIGS. 14 a-14 c are cross-sectional views of various embodiments ofventing ports for use with a reservoir connection interface apparatus oradapter.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following description, reference is made to the accompanyingdrawings which form a part hereof and which illustrate severalembodiments of the present invention. It is understood that otherembodiments may be utilized and structural and operational changes maybe made without departing from the scope of the present invention.

As shown in the drawings for purposes of illustration, the invention isembodied in an interface for connecting a syringe or a medicationreservoir to a conduit, such as infusion set tubing or an externalneedle, as well as to an infusion pump. In a one embodiment, a base isprovided which is adapted to receive a reservoir. A cap is providedwhich is adapted to be releasably coupled to the base in one of twopositions. The releasable coupler comprises a pair of detents projectingfrom the base and two pairs of detent openings in the cap which areadapted to removably engage the base detents.

A piercing member, such as a needle, is disposed in the interior of thecap in such a manner that the needle is separated from the reservoirseptum when the base detents are in the first pair of cap detentopenings, and the needle pierces the reservoir septum when the basedetents are in the second pair of cap detent openings. When thereservoir, the base and the cap are connected, an integrated unit isformed which is then capable of being inserted in the infusion pumphousing. Engagement members, such as threads, for the cap and the pumphousing are used to secure the integrated unit in the housing.

FIGS. 1 and 2 show an infusion set connector interface for attachment toa medication reservoir. The connector interface is comprised of a base 2and a cap 4. The cap 4 includes a needle 9 located internal to the caphousing. FIG. 1 is an exploded view, and therefore, the base 2 wouldnormally be fixedly attached to a reservoir 1 by securing it around theswage 3. However, alternative embodiments of the present inventioninclude a removable base so that the connector interface could be usedwith standard reservoirs, cartridges or syringes which were notinitially manufactured with the base attached.

The cap 4 portion of the connector interface is removably attached tothe base 2 with a releasable coupler. In one embodiment, the releasablecoupler is comprised of detents formed on the base 2 and detent openingsdisposed in the cap 4. Two detents 8 are disposed on the sides of thebase 2 and are spaced 180° radially apart. Only one detent 8 is shown inFIG. 1. The detents 8 are sized to fit in the two lower detent openings6, or alternatively, in the two upper detent openings 7 which are formedin the cap 4. As with the pair of detents 8, each of the lower detentopenings 6 and each of the upper detent openings 7, respectively, areradially spaced apart by 180°.

In operation, the base 2 and the reservoir 1 form an integrated unitwhich in turn is to be connected to the cap 4. In connecting thisintegrated base/reservoir unit to the cap 4, the base 2 is inserted intothe lower end of the cap 4 until the detents 8 snap into the lowerdetent openings 6. This is accomplished by moving the detents 8 overinternal cam surfaces 10 toward the lower detent openings 6. The camsurfaces act as ramps which compress the detents 8 sufficiently topermit them to snap into the lower detent openings 6. Internal threads10 a guide the detents 8 into position.

When the base/reservoir unit is in this first, lower position, theneedle 9 is positioned apart from the septum (not shown) of thereservoir 1. Thus the needle does not pierce the septum while thebase/reservoir unit is in this first position. When the base/reservoirunit is connected to the cap in this fashion, an integratedcap/base/reservoir unit is thereby formed. Such an integratedcap/base/reservoir unit can be sold or stored for long periods of timein this fashion. Alternatively the end user could assemble this unitshortly prior to placing it in the pump for use.

When the user desires to insert the cap/base/reservoir unit in the pumphousing and commence dispensing the medication through a conduit, suchas insertion set tubing 5, the base 2 is moved to the second positionwithin the cap 4. This is accomplished by twisting the base/reservoirunit while pushing it further into the cap 4. The detents 8 disengagefrom the lower detent openings 6 and engage into the upper detentopenings 7. Additional internal threads 10 a of the cap 4 serve to guidethe detents 8 over additional cam surfaces 10 from their first positionin the lower detent openings 6 to the second position in the upperdetent openings 7.

In one embodiment, the threads and the spacing between the lower detents6 and the upper detents 7 is such that a one quarter (¼) turn of thebase will cause the base/reservoir unit to travel from the first to thesecond position. The needle 9 is disposed so that when thebase/reservoir unit is in the second position, the needle pierces theseptum of the reservoir 1. Thus the movement of the base/reservoir unitfrom the first to the second position within the cap serves to cause theneedle to pierce the reservoir's septum, thus permitting the fluid inthe reservoir to flow into the needle 9 and the insertion set tubing 5.

After this connection is made, the reservoir, base and cap form a unitwhich can be releasably secured in the housing of a medication infusionpump. (not shown) Detents 4 a extend radially from the exterior of thecap and are adapted to engage into detent openings (not shown) in thepump housing. In an alternative embodiment, the cap 4 can includeexternal threads (not shown) which are used to engage the threads of thepump housing in order to secure the reservoir/base/cap unit into thehousing.

FIGS. 3 and 4 show an alternative embodiment of the infusion setconnector interface. The connector interface is comprised of a base 11and a cap 12. The cap 12 includes a needle 18 located internal to thecap housing (FIG. 4). The base 11 would normally be fixedly attached tothe reservoir 1 by securing it around the swage 3. However, alternativeembodiments of the present invention include a removable base so thatthe connector interface could be used with standard reservoirs,cartridges or syringes which were not initially manufactured with thebase attached.

The cap 12 portion of the connector interface is removably attached tothe base 11 with a releasable coupler. In this embodiment, thereleasable coupler is comprised of detents formed on the base 11 anddetent openings disposed in the cap 12. Two detents 13 are disposed onthe sides of the base 11 and are spaced 180° radially apart. Only onedetent 13 is shown in FIG. 3. The detents 13 are sized to fit in twodetent openings 14 which are formed in the cap 12. As with the pair ofdetents 13, each of the detent openings 14 are radially spaced apart by180°.

In operation, the base 11 and the reservoir 1 form an integrated unitwhich in turn is to be connected to the cap 12. In connecting thisintegrated base/reservoir unit to the cap 12, the base 11 is insertedinto the lower end of the cap 12. The detents 13 slide into matinglyshaped and longitudinally open entry slots 15 formed within the interiorwalls of the cap 12. When the base 11 is fully inserted in the cap 12,the leading edges of the detents 13 abut an annular stop shoulder 16formed within the cap 12. After the detents 13 are in this position, thebase 11 is rotated within the cap 12 toward a locked position. Referringto FIG. 4, this rotation displaces the detents 13 in a rotationaldirection for engagement with cam surfaces 17 formed within the cap 12.The rotational force on the detents 13 over the cam surfaces 17 providesa compression force on the detents 13. Continued rotation of the base 11displaces the detents 13 past the cam surfaces 17 and into alignmentwith the detent openings 14. The detents 13 enter the detent openings 14with a snap-action. Thus, the detents 13 are effectively locked withinthe detent openings 14 to prevent longitudinal separation of the base 11from the cap 12.

In the preferred embodiment, the internal needle 18 of the cap 12 isdisposed so that when the base/reservoir unit is fully inserted in thecap 12, the needle pierces the septum (not shown) of the reservoir 1.Thus the insertion force of the base/reservoir unit to the point wherethe detents 13 abut the annular stop shoulder 16 causes the needle 18 topierce the septum, thus permitting the fluid in the reservoir to flowinto the needle 18 and the insertion set tubing (not shown).

After this connection is made, the reservoir, base and cap form a unitwhich can be releasably secured in the housing of a medication infusionpump. (not shown) The cap 12 includes external threads 19 which are usedto engage the threads of the pump housing in order to secure thereservoir/base/cap unit into the housing. In the preferred embodiment,the threads 19 have an eight threads per inch (“TPI”), 2 start profile.Moreover, they have a square shaped cross section which maximizes theirholding strength. Other thread profiles and cross-sections may be usedhowever.

When disconnection of the base 11 from the cap 12 is desired, the base11 must be reverse-rotated within the cap 12, to move the detents 13past the cam surfaces 17 into re-alignment with the entry slots 15. Suchreverse-rotation of the coupler can be performed relatively easily, butessentially requires an affirmative intent by the user to disconnect thecoupling. When the detents 13 are re-aligned with the entry slots 15,the cap 12 and base 11 can be separated easily with minimal longitudinalforce.

FIG. 5 shows a cross sectional view of the reservoir/base/cap integratedunit in accordance with the embodiment of FIGS. 3 and 4. The reservoir 1includes a crimp seal swage 3 which encloses the outer periphery of therubber septum 20 in order to secure the septum 20 to the reservoir 1 andform a water tight seal. With the base 11 in the locked position asshown, the detents 13 of the base 11 are locked into the detent openings14 to securely attach the base/reservoir unit into the cap 12. Theneedle 18 pierces the rubber septum 20, thus permitting the flow ofliquid through the needle 18 and into the infusion set tubing cavity 22.Infusion set tubing (not shown) is secured into the cavity 22 to allowthe liquid to continue its flow to the user.

In the preferred embodiment, the conduit from the cap 12 is infusion settubing. However in an alternative embodiment, the conduit comprises asecond needle (not shown). This is secured into the cavity 22 with thepoint of the second needle extending outward. With this arrangement, theconnector serves as an apparatus for permitting the refilling of thereservoir 1. The second, external needle would pierce the septum of asupply vial of fluid. The fluid could then be drawn into the cap in areverse flow and into the reservoir 1 via the internal needle 18.

In the embodiment shown in FIG. 5, infusion set tubing is secured to thecavity 22 to allow liquid to flow to the user. The cavity 22 is disposedin the raised portion of the cap 12. In an alternative embodiment,however, the raised portion of the cap 12 can be in the shape of astandard luer fitting 47 shown in FIG. 13.

Referring to FIG. 5, in one embodiment the base 11 is formed around andfixedly attached to the crimp seal swage 3 portion of the reservoir 1.In an alternative embodiment, however, the base 11 is not fixedlyattached to the reservoir. Rather, the base 11 is a separate unit whichis adapted to be releasably secured to the reservoir via a friction fit.This arrangement permits the connector apparatus to be used withstandard reservoirs.

Still referring to FIG. 5, the cap 12 includes threads 19 for securingthe assembly into the pump housing (not shown). A shoulder 23 is formedas part of the cap 12 and is adapted to seat against the pump housing toform a water tight seal. This prevents any water which is exterior tothe housing from entering, thus permitting the user to engage in watersports.

The construction of these pumps to be water resistant can give rise tooperational problems. As the user engages in activities which expose thepump to varying atmospheric pressures, such as for example, swimming ortraveling in an air plane, differential pressures can arise between theinterior of the air tight/water-resistant housing and the atmosphere.Should the pressure in the housing exceed external atmospheric pressure,the resulting forces could cause the reservoir piston to be driveninward thus delivering unwanted medication. Alternatively, should thepressure in the housing be less than the external pressure, theresulting forces could cause the infusion pump motor to work harder toadvance the reservoir piston.

To address this problem, a preferred embodiment of the inventionincludes a vent which permits water resistant housing construction. Thecap 12 includes a plurality of vent ports 24, only one of which is shownin FIG. 5. The vent ports 24 permit equalization of pump housingpressure to atmospheric pressure. Hydrophobic material (not shown)covers the interior openings of the vent ports 24. Hydrophobic materialpermits air to pass through the material while preventing water or otherliquids from doing so, thus permitting water resistant venting. Thepreferred embodiment uses a hydrophobic material such as Gore-Tex®,PTFE, HDPE, or UHMW polymers from sources such as W.I. Gore &Associates, Flagstaff, Ariz., Porex Technologies, Fairburn, Ga., DeWALIndustries, Saunderstown, R.I., or Pall Specialty Materials, PortWashington, N.Y.

These materials are available in sheet form or molded (press andsintered) in a geometry of choice. Referring to FIGS. 14 a-14 c,preferred methods to attach this material to the cap 12 include moldingthe hydrophobic material into a sphere 50 (FIG. 14 a) or a cylinder 51(FIG. 14 b) and pressing it into a cavity in the pre-molded plastichousing. Alternatively, a label 52 (FIG. 14 c) of this material could bemade with either a transfer adhesive or heat bond material 53 so thatthe label could be applied over the vent port 24. Alternatively, thelabel could be sonically welded to the housing. In either method, airwill be able to pass freely, but water will not.

In an alternative embodiment which is not shown, the venting isaccomplished through a vent port located in the pump housing. This isdescribed in greater detail in copending application Ser. No. 09/429,352filed concurrently herewith, which application is incorporated byreference in its entirety. Alternatively, vent ports can be placed bothin the cap 12 as well as the pump housing.

An advantage of placing the vent port and hydrophobic material in thecap 12, as opposed to in the pump housing only, is that the infusion setand its related connectors are disposable and are replaced frequentlywith each new reservoir or vial of medication. Thus, new hydrophobicmaterial is frequently placed into service. This provides enhancedventilation as compared with the placement of hydrophobic material inonly the pump housing. Material in this location will not be replaced asoften and thus is subject to dirt or oil build up which will retardventilation.

As an alternative to the use of hydrophobic material, water can beprevented from flowing through the vent port by other apparatuses, suchas the use of relief valves.

FIG. 6 shows a cross-sectional view of the reservoir/base/cap unit inaccordance with the embodiment of FIGS. 3 and 4 which is secured into apump housing 30. The threads 19 of the cap 12 engage the pump housingthreads. Rather that the use of threads, an alternative embodiment (notshown) of the cap 12 could include detents extending radially from theexterior of the cap 12 which are adapted to engage detent openings inthe pump housing.

The shoulder 23 portion of the cap 12 seats against the pump housing 30to permit water tight construction. Further aiding in the water tightconstruction is an O-ring seal 31 which is disposed in the pump housing30 and located just above the shoulder 23. In the preferred embodiment,the vent material 32 is comprised of hydrophobic material and is sonicwelded to the upper interior surface of the cap 12. Alternatively, thevent material 32 could be attached to the cap 12 with an adhesive. Thevent ports are not shown in FIG. 6.

Although the foregoing description of the venting was in connection withthe embodiment of FIGS. 3-6, this feature is also applicable to theembodiment of FIGS. 1-2.

FIGS. 7 and 8 show an alternative embodiment of the cap 12. Referring toFIG. 7, a cap engagement member consists of a detent arm 34 which isformed in the upper portion of the cap 12. The purpose of the detent arm34 is to securely engage the cap 12 into the pump housing. FIG. 8 showsa top view of the cap 12 positioned in the pump housing 30. The pumphousing 30 has two case lock recesses 35 disposed in the circular rim ofthe housing. The detent arm 34 snaps into either of the case lockrecesses 35. This engagement results in a “click” when the cap 12 isappropriately seated, thus providing both tactile and audible feedbackto the user that the cap is securely engaged in the pump housing.Moreover, the detent arm 34 aligning with the recess 35 also serves as avisual indicator that the cap 12 is appropriately seated.

FIG. 9 shows an alternative embodiment of the cap 12 which contains achild safety feature. The cap 12 includes a locking member whichconsists of a safety tab 36 disposed in a groove 37. The safety tab 36is sized such that it is able to slide along the length of the groove37. When the safety tab 36 is in the position shown in FIG. 9, thedetent arm 34 is unable to retract from its engaged position. Thus whenthe cap 12 is seated into the pump housing 30 (not shown) and the detentarm is seated into the case lock recess 35 (not shown), the safety tab36 will prevent the detent arm 34 from disengaging from the case lockrecess 35 thus more securely locking the cap 12 in the pump housing.

Thus for example, a parent could slide the safety tab 36 from theunlocked location in the groove 37 to the locked location shown in FIG.9 so that it would be more difficult for a young child or infant toinadvertently remove the cap/base/reservoir unit from the pump housing.On the other hand, when the safety tab 36 is moved to the opposite endof the groove 37, the detent arm 34 is able to retract thus permittingremoval of the cap 12 from the pump housing.

Although the foregoing description of the cap engagement member andchild safety tab was in connection with the embodiment of FIGS. 3-9,this feature is also applicable to the embodiment of FIGS. 1-2.

FIG. 10 shows an exploded view of the cap 12 and the vent material 32.In the preferred embodiment, the vent material is made of hydrophobicmaterial and is formed in a circular shape with a circular hole in thecenter. The vent material 32 is attached to the upper interior surface38 of the cap 12 via sonic welding or an adhesive. When it is soattached, the needle 18 protrudes through the center hole of the ventmaterial 32 but the interior openings of the vent ports 24 (not shown)are covered.

FIGS. 11 and 12 show an embodiment of the present invention where anadapter 40 is provided to allow a standard style syringe 41 with anintegrated luer fitting 42 to be mounted and sealed in the pump housing.The syringe 41 is inserted through the center of the adapter 40 and heldinto place by a friction fit. The O-ring seal 43 in the adapter 40 seatsagainst the syringe wall in order to prevent water and dirt fromentering the pump housing.

A shoulder 45 is formed as part of the adapter 40 and is adapted to seatagainst the interior of the pump housing to form a water tight seal. Twotabs 44 are formed on the top surface of the adapter 40 and provide asurface for the user to grip the adapter 40 and twist it so that theadapter threads 19 engage the threads (not shown) of the pump housing. Adetent arm 34 is formed in the upper portion of the adapter 40. Itspurpose is to securely lock the adapter 40 into the pump housing (notshown) in the same manner as is shown in FIG. 8. Although not shown inFIGS. 11 and 12, the adapter 40 can further contain vent ports coveredwith hydrophobic material or a relief valve in order to permit waterresistant venting of the pump housing in the same manner as previouslydescribed with other embodiments.

FIG. 13 shows another embodiment of the present invention where aninterface is provided to connect a reservoir to a conduit, such astubing, via a standard luer fitting connection. This allows a luer styledisposable infusion set to connect to the pump housing (not shown). Acap 46 is formed with a luer fitting 47 portion as an integral partthereof. Except for the shape of the luer fitting 47 portion, the cap 46has all of the other features of the cap 12 shown in FIG. 5. Thusreferring to FIG. 13, the cap 46 is comprised of, among other things,threads 19, detent openings 14, a shoulder 23, vent ports 24, a detentarm 34, and a needle (not shown) disposed in the interior of the cap 46.

While the description above refers to particular embodiments of thepresent invention, it will be understood that many modifications may bemade without departing from the spirit thereof. The accompanying claimsare intended to cover such modifications as would fall within the truescope and spirit of the present invention. The presently disclosedembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than the foregoing description,and all changes which come within the meaning and range of equivalencyof the claims are therefore intended to be embraced therein.

1. A medication reservoir, comprising: a reservoir; a swage coupled tothe reservoir enclosing an outer periphery of a septum to secure theseptum to the reservoir; a base attached to the reservoir secured aroundthe swage, wherein the base includes at least one slot along sides ofthe base; a first detent disposed on the sides of the base to releasablyengage a first detent opening in a cap, wherein the first detent iscompressed by an interior wall of the cap as the first detent isslidably moved to engage the first detent opening in the cap; and asecond detent, wherein the second detent: is disposed on the sides ofthe base and spaced 180 degrees radially apart from the first detent:releasably engages a second detent opening in the cap spaced 180 degreesradially apart from the first detent opening; and is compressed by theinterior wall of the cap as the second detent is slidably moved toengage the second detent opening in the cap.
 2. The medication reservoirof claim 1, wherein the base is fixedly attached to the reservoir. 3.The medication reservoir of claim 1, wherein the base is releasablysecured to the reservoir.
 4. The medication reservoir of claim 1,wherein the first detent enters the first detent opening with asnap-action.
 5. The medication reservoir of claim 1, further includingthe cap.
 6. The medication reservoir of claim 5, wherein the capincludes a needle internal to the cap to pierce the septum.
 7. Themedication reservoir of claim 1, wherein the base includes a second slotalong the sides of the base.
 8. The medication reservoir of claim 1,wherein the reservoir includes a movable piston with an O-ring to form awater tight seal.
 9. A medication reservoir, comprising: a reservoir; aswage coupled to the reservoir enclosing an outer periphery of a septumto secure the septum to the reservoir; a base attached to the reservoirsecured around the swage, wherein the base includes at least one slotalong sides of the base; a first detent disposed on the sides of thebase to releasably engage a first detent opening in a cap upon rotationof the base, wherein: the first detent is rotated along an interior wallof the cap to engage the first detent opening in the cap; and the capcomprises internal cam surfaces on the interior wall of the cap that actas ramps which compress the first detent as the base is rotated toengage the cap.
 10. A medication reservoir, comprising: a reservoir; aswage coupled to the reservoir enclosing an outer periphery of a septumto secure the septum to the reservoir; a base attached to the reservoirsecured around the swage, wherein the base includes at least one slotalong sides of the base; a first detent disposed on the sides of thebase to releasably engage a first detent opening in a cap upon rotationof the base, wherein: the first detent is rotated along an interior wallof the cap to engage the first detent opening in the cap; and a seconddetent disposed on the sides of the base and spaced 180 degrees radiallyapart from the first detent, wherein: the second detent is compressed bythe interior wall of the cap; and the second detent is rotated along theinterior wall of the cap to engage a second detent opening in the cap.11. The medication reservoir of claim 10, further including: a cap,removably attachable to the base, having: the first detent opening toreceive the first detent; and the second detent opening to receive thesecond detent.
 12. The medication reservoir of claim 11, wherein the capcomprises cam surfaces formed in the interior wall of the cap, whereinthe cam surfaces provide a compression force on the first detent and thesecond detent as the base is rotated to engage the cap.
 13. Themedication reservoir of claim 10, wherein the first and second detentsenter the first detent opening with a snap-action such that the firstand second detents are locked within the first and second detentopenings to prevent longitudinal separation of the base from the cap.14. A medication reservoir, comprising: a reservoir; a swage coupled tothe reservoir enclosing an outer periphery of a septum to secure theseptum to the reservoir; a cap comprising: a first detent opening; asecond detent opening; and a needle internal to the cap to pierce theseptum; a base attached to the reservoir secured around the swage,wherein the base includes at least one slot along sides of the base; afirst detent disposed on the sides of the base to releasably engage thefirst detent opening in the cap, a second detent disposed on the sidesof the base to releasably engage the second detent opening in the cap,wherein the first detent and the second detent are compressed by aninterior wall of the cap as the first and second detents are rotatedalong the interior wall of the cap to engage the first and the seconddetent openings in the cap; and the needle is disposed in the cap topierce the septum when the first and second detents are engaged with thefirst and the second detent openings in the cap.
 15. The medicationreservoir of claim 14, wherein the first detent and the second detentare spaced 180 degrees radially apart.
 16. The medication reservoir ofclaim 14, wherein the cap comprises a vent that permits the passage ofair and inhibits the passage of fluids.
 17. The medication reservoir ofclaim 14, wherein the first detent and the second detent enter the firstand the second detent openings with a snap-action.
 18. The medicationreservoir of claim 17, wherein the cap comprises an annular stopshoulder that abuts the first and second detents when the base is fullyinserted in the cap.
 19. The medication reservoir of claim 14, whereinthe reservoir includes a movable piston with an O-ring to form a watertight seal.
 20. The medication reservoir of claim 14, wherein the capcomprises internal threads that guide the first and the second detentsas the cap engages the base.